commit 7181502a6495175d314556b55854c001680f9615 Author: Nixietab <75538775+nixietab@users.noreply.github.com> Date: Wed Sep 2 12:53:50 2026 -0300 first commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..517d92e --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +nutils +data/ +*.mmdb diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..feb1b3a --- /dev/null +++ b/LICENSE @@ -0,0 +1,278 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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Returns client IP, reverse DNS, geolocation, and ASN info in plain text. + +## Build + +```sh +go build -o nutils +``` + +## Usage + +```sh +./nutils # uses nutils.toml in cwd +./nutils -c /etc/nutils.toml +``` + +## License + +GPL-2.0 diff --git a/config.go b/config.go new file mode 100644 index 0000000..aed7ec7 --- /dev/null +++ b/config.go @@ -0,0 +1,50 @@ +package main + +import ( + "os" + + "github.com/BurntSushi/toml" +) + +type ServiceConfig struct { + Enabled bool `toml:"enabled"` + Subdomains []string `toml:"subdomains"` + Directories []string `toml:"directories"` +} + +type Config struct { + Server struct { + Listen string `toml:"listen"` + } `toml:"server"` + Services map[string]ServiceConfig `toml:"services"` + Geo struct { + AsnDB string `toml:"asn_db"` + CityDB string `toml:"city_db"` + DownloadURLAsn string `toml:"download_url_asn"` + DownloadURLCity string `toml:"download_url_city"` + CacheDir string `toml:"cache_dir"` + } `toml:"geo"` +} + +func LoadConfig(path string) (*Config, error) { + var cfg Config + + f, err := os.Open(path) + if err != nil { + return nil, err + } + defer f.Close() + + if _, err := toml.NewDecoder(f).Decode(&cfg); err != nil { + return nil, err + } + + if cfg.Server.Listen == "" { + cfg.Server.Listen = ":8080" + } + if cfg.Geo.CacheDir == "" { + cfg.Geo.CacheDir = "data" + } + + return &cfg, nil +} diff --git a/doc.md b/doc.md new file mode 100644 index 0000000..946678c --- /dev/null +++ b/doc.md @@ -0,0 +1,61 @@ +# nutils + +## Response + +Every request returns 5 lines of plain text: + +``` +203.0.113.42 +host-203-0-113-42.example.net +proxy=NO, type=UNKNOWN, tor=NO +North America, United States, Los Angeles +Example ISP / AS12345 +``` + +| Line | Field | Meaning | +|------|-------|---------| +| 1 | IP | Client public IP (from X-Forwarded-For, X-Real-IP, or remote addr) | +| 2 | Reverse DNS | PTR record, or "Unknown" | +| 3 | Classification | Abuse flags | +| 4 | Location | Continent, country, city (GeoLite2-City) | +| 5 | ASN | Organization and ASN number (GeoLite2-ASN) | + +## Modes + +**ip** (default) +Returns both IPv4 and IPv6. Works as a catch-all. + +**ip4** +IPv4 only. Rejects IPv6 clients with HTTP 400. + +**ip6** +IPv6 only. Rejects IPv4 clients with HTTP 400. + +## Config + +```toml +[server] +listen = ":8080" + +[services.ip] +enabled = true +subdomains = ["ip.example.com"] +directories = ["/"] + +[services.ip4] +enabled = true +subdomains = ["ip4.example.com"] + +[services.ip6] +enabled = true +subdomains = ["ip6.example.com"] + +[geo] +asn_db = "GeoLite2-ASN.mmdb" +city_db = "GeoLite2-City.mmdb" +download_url_asn = "https://git.io/GeoLite2-ASN.mmdb" +download_url_city = "https://git.io/GeoLite2-City.mmdb" +cache_dir = "data" +``` + +Services can be toggled on/off with `enabled`. MMDBs are downloaded automatically on first run and cached in `cache_dir`. \ No newline at end of file diff --git a/geo.go b/geo.go new file mode 100644 index 0000000..af57ee3 --- /dev/null +++ b/geo.go @@ -0,0 +1,136 @@ +package main + +import ( + "fmt" + "io" + "net" + "net/http" + "os" + "path/filepath" + + "github.com/oschwald/maxminddb-golang" +) + +type Geo struct { + asn *maxminddb.Reader + city *maxminddb.Reader +} + +type ASNResult struct { + AutonomousSystemNumber uint `maxminddb:"autonomous_system_number"` + AutonomousSystemOrganization string `maxminddb:"autonomous_system_organization"` +} + +type CityResult struct { + Continent struct { + Names map[string]string `maxminddb:"names"` + } `maxminddb:"continent"` + Country struct { + Names map[string]string `maxminddb:"names"` + } `maxminddb:"country"` + City struct { + Names map[string]string `maxminddb:"names"` + } `maxminddb:"city"` +} + +func DownloadFile(url, dest string) error { + if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil { + return err + } + + fmt.Printf("downloading %s -> %s\n", url, dest) + + resp, err := http.Get(url) + if err != nil { + return err + } + defer resp.Body.Close() + + if resp.StatusCode != 200 { + return fmt.Errorf("HTTP %d for %s", resp.StatusCode, url) + } + + out, err := os.Create(dest) + if err != nil { + return err + } + defer out.Close() + + _, err = io.Copy(out, resp.Body) + return err +} + +func ensureMMDB(url, path string) error { + if _, err := os.Stat(path); err == nil { + return nil + } + return DownloadFile(url, path) +} + +func InitGeo(cfg *GeoConfig) (*Geo, error) { + if err := ensureMMDB(cfg.AsnURL, cfg.AsnPath); err != nil { + return nil, fmt.Errorf("ASN DB: %w", err) + } + if err := ensureMMDB(cfg.CityURL, cfg.CityPath); err != nil { + return nil, fmt.Errorf("City DB: %w", err) + } + + asn, err := maxminddb.Open(cfg.AsnPath) + if err != nil { + return nil, fmt.Errorf("open ASN DB: %w", err) + } + city, err := maxminddb.Open(cfg.CityPath) + if err != nil { + asn.Close() + return nil, fmt.Errorf("open City DB: %w", err) + } + + return &Geo{asn: asn, city: city}, nil +} + +func (g *Geo) Close() { + g.asn.Close() + g.city.Close() +} + +type GeoInfo struct { + ASN string + Org string + Continent string + Country string + City string + ReverseDNS string +} + +func (g *Geo) Lookup(ip net.IP) GeoInfo { + info := GeoInfo{ReverseDNS: "Unknown"} + + hosts, err := net.LookupAddr(ip.String()) + if err == nil && len(hosts) > 0 { + info.ReverseDNS = hosts[0] + } + + var asn ASNResult + if err := g.asn.Lookup(ip, &asn); err == nil { + if asn.AutonomousSystemNumber > 0 { + info.ASN = fmt.Sprintf("AS%d", asn.AutonomousSystemNumber) + info.Org = asn.AutonomousSystemOrganization + } + } + + var cr CityResult + if err := g.city.Lookup(ip, &cr); err == nil { + info.Continent = cr.Continent.Names["en"] + info.Country = cr.Country.Names["en"] + info.City = cr.City.Names["en"] + } + + return info +} + +type GeoConfig struct { + AsnURL string + CityURL string + AsnPath string + CityPath string +} diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..4c7797e --- /dev/null +++ b/go.mod @@ -0,0 +1,10 @@ +module nutils + +go 1.26.2 + +require ( + github.com/BurntSushi/toml v1.6.0 + github.com/oschwald/maxminddb-golang v1.13.1 +) + +require golang.org/x/sys v0.21.0 // indirect diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..85fbbea --- /dev/null +++ b/go.sum @@ -0,0 +1,14 @@ +github.com/BurntSushi/toml v1.6.0 h1:dRaEfpa2VI55EwlIW72hMRHdWouJeRF7TPYhI+AUQjk= +github.com/BurntSushi/toml v1.6.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho= +github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= +github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= +github.com/oschwald/maxminddb-golang v1.13.1 h1:G3wwjdN9JmIK2o/ermkHM+98oX5fS+k5MbwsmL4MRQE= +github.com/oschwald/maxminddb-golang v1.13.1/go.mod h1:K4pgV9N/GcK694KSTmVSDTODk4IsCNThNdTmnaBZ/F8= +github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= +github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= +github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg= +github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY= +golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws= +golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA= +gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA= +gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= diff --git a/main.go b/main.go new file mode 100644 index 0000000..27c89a6 --- /dev/null +++ b/main.go @@ -0,0 +1,38 @@ +package main + +import ( + "flag" + "fmt" + "log" + "net/http" + "path/filepath" +) + +func main() { + cfgPath := flag.String("c", "nutils.toml", "config file path") + flag.Parse() + + cfg, err := LoadConfig(*cfgPath) + if err != nil { + log.Fatalf("config: %v", err) + } + + geo, err := InitGeo(&GeoConfig{ + AsnURL: cfg.Geo.DownloadURLAsn, + CityURL: cfg.Geo.DownloadURLCity, + AsnPath: filepath.Join(cfg.Geo.CacheDir, filepath.Base(cfg.Geo.AsnDB)), + CityPath: filepath.Join(cfg.Geo.CacheDir, filepath.Base(cfg.Geo.CityDB)), + }) + if err != nil { + log.Fatalf("geo init: %v", err) + } + defer geo.Close() + + services := BuildServices(cfg) + if len(services) == 0 { + log.Fatal("no services enabled") + } + + fmt.Printf("nutils listening on %s with %d services\n", cfg.Server.Listen, len(services)) + log.Fatal(http.ListenAndServe(cfg.Server.Listen, Handle(services, geo))) +} diff --git a/nutils.toml b/nutils.toml new file mode 100644 index 0000000..5ae5ae4 --- /dev/null +++ b/nutils.toml @@ -0,0 +1,22 @@ +[server] +listen = ":8080" + +[services.ip] +enabled = true +subdomains = ["ip.example.com"] +directories = ["/"] + +[services.ip4] +enabled = true +subdomains = ["ip4.example.com"] + +[services.ip6] +enabled = true +subdomains = ["ip6.example.com"] + +[geo] +asn_db = "GeoLite2-ASN.mmdb" +city_db = "GeoLite2-City.mmdb" +download_url_asn = "https://git.io/GeoLite2-ASN.mmdb" +download_url_city = "https://git.io/GeoLite2-City.mmdb" +cache_dir = "data" diff --git a/server.go b/server.go new file mode 100644 index 0000000..b23f559 --- /dev/null +++ b/server.go @@ -0,0 +1,138 @@ +package main + +import ( + "fmt" + "net" + "net/http" + "strings" +) + +type Service struct { + Name string + Subdomains map[string]bool + Directories map[string]bool + FilterV4 bool + FilterV6 bool +} + +func BuildServices(cfg *Config) map[string]*Service { + services := make(map[string]*Service) + + for name, sc := range cfg.Services { + if !sc.Enabled { + continue + } + svc := &Service{ + Name: name, + Subdomains: make(map[string]bool), + Directories: make(map[string]bool), + } + for _, s := range sc.Subdomains { + svc.Subdomains[strings.ToLower(s)] = true + } + for _, d := range sc.Directories { + svc.Directories[d] = true + } + switch name { + case "ip4": + svc.FilterV4 = true + case "ip6": + svc.FilterV6 = true + } + services[name] = svc + } + return services +} + +func extractIP(r *http.Request) net.IP { + if xff := r.Header.Get("X-Forwarded-For"); xff != "" { + parts := strings.Split(xff, ",") + if ip := net.ParseIP(strings.TrimSpace(parts[0])); ip != nil { + return ip + } + } + if xri := r.Header.Get("X-Real-IP"); xri != "" { + if ip := net.ParseIP(strings.TrimSpace(xri)); ip != nil { + return ip + } + } + host, _, err := net.SplitHostPort(r.RemoteAddr) + if err != nil { + return net.ParseIP(r.RemoteAddr) + } + return net.ParseIP(host) +} + +func matchService(host, path string, services map[string]*Service) *Service { + hostname := host + if i := strings.IndexByte(host, ':'); i != -1 { + hostname = host[:i] + } + + for _, svc := range services { + if svc.Subdomains[hostname] { + return svc + } + } + + parts := strings.Split(hostname, ".") + if len(parts) >= 2 { + label := parts[len(parts)-2] + for _, svc := range services { + if svc.Subdomains[label] { + return svc + } + } + } + + for _, svc := range services { + if svc.Directories[path] { + return svc + } + } + return nil +} + +func Handle(services map[string]*Service, geo *Geo) http.HandlerFunc { + return func(w http.ResponseWriter, r *http.Request) { + svc := matchService(r.Host, r.URL.Path, services) + if svc == nil { + http.NotFound(w, r) + return + } + + ip := extractIP(r) + if ip == nil { + http.Error(w, "cannot determine client IP", 500) + return + } + + isV4 := ip.To4() != nil + if (svc.FilterV4 && !isV4) || (svc.FilterV6 && isV4) { + http.Error(w, fmt.Sprintf("this endpoint requires %s", map[bool]string{true: "IPv6", false: "IPv4"}[svc.FilterV6]), 400) + return + } + + info := geo.Lookup(ip) + + fmt.Fprintf(w, "%s\n", ip) + fmt.Fprintf(w, "%s\n", info.ReverseDNS) + fmt.Fprintf(w, "proxy=NO, type=UNKNOWN, tor=NO\n") + continent, country, city := info.Continent, info.Country, info.City + if continent == "" { + continent = "Unknown" + } + if country == "" { + country = "Unknown" + } + if city == "" { + city = "Unknown" + } + fmt.Fprintf(w, "%s, %s, %s\n", continent, country, city) + if info.Org != "" { + fmt.Fprintf(w, "%s / %s\n", info.Org, info.ASN) + } else { + fmt.Fprintf(w, "Unknown\n") + } + } +}